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GLIN==> Battling the Beetle

July 20, 2001

Source: James E. Appleby, (217) 244-3431
Contact: Debra Levey Larson
Communications Specialist
(217)244-2880; dlarson@uiuc.edu


NOTE: Photos suitable for downloading are available at:

Battling the Beetle

URBANA- The good news is that the Asian longhorned beetle cannot fly very far. While residents in Ravenswood, Addison and Summit, Illinois as well as a forest preserve near Park Ridge where the beetle has already infested trees, will probably not agree that this is good news for them, it could be a blessing to neighboring Chicago suburbs.

James Appleby, Entomologist at the University of Illinois in the College of Agricultural, Consumer and Environmental Sciences studies the Asian longhorned beetle and described why it is not a long-distance flyer. "It's a big, heavy beetle, so it can fly but not very far. They may fly from one tree to the next, but not five or 10 miles." Appleby did add that although the beetles cannot fly very far, they can be transported by cars. "They can hitch a ride on the grill of your car, get off and lay eggs in their new location," he said. The beetles may also travel in logs destined to be used as firewood. Appleby explained that a log might be infested with the beetles in their larval or pupal stage and go unnoticed when people load the logs into their van to take home.

Cutting down the tree in which larvae or pupae are discovered is one method being used to control the beetle. Unfortunately, it also eliminates the tree. "In the infested areas of Chicago, some trees that showed no symptoms of beetle infestations were treated with the systemic chemical, imidacloprid (Merit)," Appleby said, "It was injected into the bark to hopefully kill any tiny larvae that might develop in the trees."

Besides destroying the tree and attempts at some chemical treatments, biological control is another method being explored. "Investigations are being conducted in China to locate biological controls that might be effective, however it must be understood that even in China the beetle is a serious tree pest," Appleby explained. "Currently the use of some nematodes are being tested at United States Department of Agriculture Forest Service laboratories and at the Illinois Natural History Survey to see if their use in the field may be practical."

All species of maples are the beetle's tree of choice, but they can also infest elm, horsechestnut, poplar, willow, and boxelder trees. Adult beetles may be seen from late May through October. The body of the adult beetle (excluding the antennae) is about 1 1/4 inches in length and shiny black with small, white marking on its wing coverings. The long antennae are banded in black and white.

The Asian longhorned beetle has only been a problem pest in specific regions in New York (Brooklyn, Amityville, Bayside, Queens, Islip, Manhattan and Flushing Meadows) and near Chicago (Ravenswood, Addison, Summit, and a forest preserve near Park Ridge). What do these areas have in common? Both New York and Chicago are particularly susceptible to the invasion of non-native species due to the high traffic of imported goods into the two cities. In the case of the beetles, it is presumed that they entered the United States via wooden crates shipped from China. They were first spotted in the Chicago area in July 1998. Another factor is that trees in urban areas like New York and Chicago are often stressed by crowding and drought conditions, making them more vulnerable to attack.

Appleby said that even though the beetle is currently being well-monitored and controlled, it is still a major threat to Illinois forests. "It looks like The Illinois Department of Agriculture, in cooperation with the United States Department of Agriculture (USDA) Forest Service, USDA Animal and Plant Health Inspections Service, and the Chicago Bureau of Forestry are doing an excellent job of eliminating the beetle in Chicagoland. They continually scout from tree to tree and eliminate infested trees," he said.

Although it is yet to be shown whether or not the injection of imidacloprid has been effective, Stan Smith, manager of the nursery program for the Illinois Department of Agriculture said, "The beetles were spotted in New York around July 1st but we haven't seen a beetle here since last summer, so that's good. We are concerned about a known infestation in one forest preserve near Park Ridge, but have not been able to get into the area to survey for the presence of the beetle." Smith explained that the foliage is so dense at this time of year that it is difficult for workers to get in to check. "We'll do an extensive survey after the leaves come off of the trees," he said. Smith said that 35,000 trees were injected with imidacloprid between mid April to mid June of this year.

The City of Chicago has replaced the destroyed trees with trees that are less susceptible to beetle attack such as Kentucky coffee tree, Turkish filbert, ginkgo, catalpa, linden, tulip-tree, and honeylocust. And Smith said that the areas which have reported infestations are quarantined. "You can't cut a tree down in the City of Chicago without a permit and all of the tree trimming companies are under a compliance agreement that states that they will not transport infested tree limbs out of the area," said Smith. For detailed maps of the quarantine areas see the Illinois Department of Agriculture Web site at http://www.agr.state.il.us/beetle.html

Recently transplanted trees and stressed trees are always the most vulnerable to attack, so taking care of the tree is one way Appleby said tree owners can reduce the chances of an invasion. "Following good practices like watering trees during drought periods, pruning when needed, using mulch, and planting a variety of less susceptible tree species are some of the ways you can reduce the chances of beetle attack."

The female beetle chews small funnel shaped depressions in tree bark. Then it inserts an egg under the bark. After hatching, the beetle larva feeds under the bark. As it matures, it enters the heartwood. The overwintering larvae change into the pupa stage in late spring and summer. The adult beetle chews its way out of the wood leaving an exit hole about 7/8 of an inch in diameter. There are a number of native longhorned beetles with similar habits, so seeing exit holes does not mean that the tree is infested with Asian longhorned beetles. But, if you see what you think might be damage from an Asian longhorned beetle, report it immediately to the Illinois Department of Agriculture by calling 1-800-641-3934.

A color leaflet showing photos of the beetle and damage is available from the University of Illinois, Department of NRES, 1102 S. Goodwin Ave., Urbana, IL 61801. Request Asian longhorned beetle leaflet 100In.


Debra Levey Larson, Media/Communications Specialist
Information, Technology & Communication Services
University of Illinois
65 Mumford Hall, MC-710
1301 W. Gregory Dr.
Urbana, IL 61801
Phone: 217-244-2880
Fax: 217-333-2614
E-mail: dlarson@uiuc.edu

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